Near-infrared photothermal effect enhanced heterogeneous catalysis of Co3O4/PDA composite for highly efficient activation of peroxymonosulfate to degrade antibiotic pollutants

The utilization of near-infrared (NIR) light with strong photothermal effect in photo-Fenton or Fenton-like systems for the degradation of organic pollutants is always ignored. In this study, we have synthesized a novel photothermal Fenton-like catalyst (Co3O4/PDA) to activate peroxymonosulfate (PMS) for the degradation of antibiotics. The Co3O4 in the nanocomposite acts as a PMS activator, while unexpectedly, PDA was found to accelerate the redox cycle of Co2+/Co3+. Both Co3O4 and PDA are black-colored photothermal materials with excellent NIR absorption properties. During the degradation process, the light-to-heat conversion ability of Co3O4 and PDA enables a higher temperature, which innovatively boosts the rate of PMS catalytic activation. Mechanistic studies revealed that the increased temperature effectively promotes the heterogeneous catalytic PMS activation by Co3O4/PDA. As a result, the Co3O4/PDA + PMS + NIR system exhibits greatly enhanced degradation performance. Furthermore, this degradation system demonstrates strong tolerance to different operation conditions, and the catalyst exhibits good stability in cycling tests. These results demonstrate the favorable application prospects of this photothermal Fenton-like system in environmental water remediation. The findings also contribute valuable insights towards the development of efficient strategies for the photothermal activation of PMS.